1. Field of the Invention
The present invention relates to wireless communication apparatuses and, in particular, to antennas and wireless IC devices used in radio frequency identification (RFID) systems.
2. Description of the Related Art
In recent years, as article management systems, RFID systems have been developed in which communication is performed by using a non-contact method in which an electromagnetic field is utilized to transmit predetermined information between a reader/writer, which generates an induction field, and an IC tag (hereafter referred to as a wireless IC device), which is attached to an article and stores predetermined information therein.
A known wireless IC device used in such an RFID system includes a wireless IC chip that processes predetermined radio signals and a radiation electrode pattern that transmits and receives radio signals, and is disclosed, for example, in International Unexamined Publication No. WO2007/083574. International Unexamined Publication No. WO2007/083574 discloses an example of a radiation electrode pattern that includes a patch electrode.
However, there is a problem with radiation electrodes that include a patch electrode in that, for example, it is necessary to provide a feeder pin arranged to feed a signal to the patch electrode inside an insulating board and to provide a feeder electrode on a side surface of the board. The formation of such a feeder portion is difficult, the manufacturing process is complicated, and a poor connection with the radiation electrode occurs at an edge portion of the insulating board.